Ingot-casting.



A. G. MGKENNA.

INGOT CASTING.`

APPLICATION FILED MAY16,1912,

Patented Dec. 1, 1914.

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l forts from a practical encircle trattenne., or Wasrrrrreron, nrsrnrcr or consistere..

INGOT-CASTING.

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Specicaticn. of Letters Patent.

Patented Bee., il, lll-5rd.,

Application filed May 16, 1912. Serial No. el'.

To all whom it may concern:

Be it known that l, ALEXANDER Gnonen McKenna, a citizen of the United States, residing at Washington, in the District of Co lumbia, have invented certain new and use ful lmproveinents in bigot-Casting; and l do hereby declare the following to be a full, clear, and exact description ol? the same, relerence being had to the accompanying drawings, forming part o't'his specification, and tothe ligures and letters of reference marked thereon.

This invention relates to improvements in metal casting and particularly the casting of ingots of steel and similar metal.

lit is Well known that in casting'ingots the metal in solidifying forms cavities or pipes, and While many attempts hare been made to prevent such piping or the forma tion or" cavities or to cure the defects resulting from the formation of the saine, such efstandpoint have usually resulted in indiderent success. Because of this and the extra cost and labor, casting operations are usually carried on Without serious eiiort to overcome the diiiculty with the result that the castings and articlesmanufactured from the castings are defective and liable to develop aws and break down unexpectedly at points Where the metal should be solid and homogeneous.

l have discovered that a complete cure for the diliculty consists in filling the cavities or piping at the 'time of casting, and While the metal is still hot, with molten metal of the same or substantially the same composition as the casting, the heat of the added metal being much higher than that necessary or employed-'in melting the metal for the body of the casting, whereby the added metal will not only penetrate the interstices formed in the casting, but Will Without the use of an excess of metal supply suiicient heat to melt down any obstructions and lorrn a homogeneous mass with the Walls of the cavi-ties or interstices by fusing'the'same.

"With furnaces in which the steel is melted in crucibles or in a hearth through radiation from flames, it is diiiicult to superheat the steel suciently,

stroyed, but electric furnaces in which the steel may. be heated, to a higher degree than l the Walls df the container may be employed former into the latter.

as the container will be demelts down and. the metal readily heated to the temperature, heated.

lt is preferred that the metal to be supplied to the casting shall be superheated in a relatively small portable furnace made in the forni or a ladle Witha bottom discharge, so as to avoid loss of heat during transference and to permit of the heat being maintained to the very moment when the metal passes from the ladle to the casting.

ln the dnawings.--l*`igure l is a. conventional section showing a ladle and ingot mold, with molten metal desired conveniently termed super- Fig. 2 is a similar section oi the ingot mold after the metal has congealed therein. Fig. 3 is a similar section of a small superheating ladle. Fig. l is a similar section of the small superheating ladle and ingo*L mold showing the method oi'V illing the pipe in the ingot.

Like letters ci' reference in the several figures indicate the same parts.

ln practice the steel will lie-melted, as usual, in an open hearth or other suitable furnace from which it will be drawn into a large ladle such as A., Fig. l adapted to be tapped from the bottom. When the slag begins to run from the furnace the large ladle is removed by a crane and asmall electric furnace ladle such as B placed in position to receive a portion of the slag, suiiicient to cover any metal Which may be subsequently poured into the ladle. A suitable quantity of the molten steel is non7 drawn from the large ladle into the srnall electric furnace ladle, and the large ladle is carried to the molds (C in the drawing) and poured (Fig. l) in the usual manner. During this'operation or at the proper time current is supplied to the small ladlev (an A. C. generator D being indicated in F ig. 3 of the drawing for this purpose) and the metal in the small ladle is superheated. lVhen the cast-ings have cooled to a point Where the piping has taken place or the cavities Lhave formed (Fig. 2), the time depending upon the size oi the ingots or castings, the electric furnace ladle is carried over the molds and the pipes or cavities lled with the superheated steel (as shown in. Fig. @The superheated steel not Ionly lls all cavities and interstices, but any obstructions and becomes flowing from the completely homogeneous with the body of the casting.

Obviously the slag coverings for the metal in the ladies need not be employed, but are desirable toy conserve the heat and protect the surface of the metal during the pouring and heating operations..

With the present invention there is no eX- cess of metal used and consequently no Waste. The process is economical both because of the saving of metal and because it is only necessary to superheat a relatively small percentage of the metal for making the casting.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The process of casting ingots in molds which consists in pouring the metal into the mold and permitting the same to congeal, then pouring into the pipes and interstices therein molten metal sufficient in quantity to ill the pipes and interstices Without excess, said molten metal being superheated to a temperature suflicient to fuse the Walls of the pipes and interstices and unite therewith to form a homogeneous mass.

2. TheV improvement in the process of casting ingots Which consists in filling the pipes and interstices therein with superheated molten metal of substantially the composition of the body of the ingot.

3. The improvement in the process of casting ingots, which consists in superheating a relatively small percentage of the molten metal from which the ingot is cast and in filling the pipes and interstices in the ingot With the superheated metal.

4. rlhe improvement in the process of casting ingots which consists in superheating a portion of the molten metal in a movable heater and in transferring the heater to and discharging the superheated metal therefrom directly into the pipes and interstices in the ingot.

ALEXANDER GEORGE MCKENNA.

Witnesses HARRY F. CLARK,

WALTER ANDERSON. 

